This invention relates to a scanning apparatus which carries out time sequence scanning and photoelectrically converts the resultant optical data into electric signals.
A large number of processes are already known for scanning optical data impressed on the surface of a manuscript sheet such as a single paper sheet or the respective pages of a book by light beams, for example, laser beams and photoelectrically converting the resultant reflections into electric signals. Since, in this case, the central portion of the manuscript sheet is positioned remotest from the surrounding photoelectric conversion elements, problems have been raised due to an undesirable phenomenon generally referred to as "shading" appearing in the central portion of the manuscript sheet. This shading phenomenon becomes noticeable particularly when the manuscript sheet has a large size.